1. Field of the Invention
The present invention pertains to land vehicles generally, and more specifically to an apparatus used to interconnect a towing and transporting vehicle to a transported load. In one embodiment, the transported load is a second land vehicle, and may include such diverse vehicles as automobiles, utility trucks, motorcycles, trailers and other vehicles and non-vehicles. In a more specific embodiment, the invention pertains to a multi-purpose apparatus which enables an automobile or utility vehicle to conveniently be towed behind a mobile home, recreational vehicle, camper or the like.
2. Description of the Related Art
When a first vehicle is used to tow a second, a variety of schemes have been proposed to enable satisfactory towing. In one approach, the second vehicle is connected to the first through a flaccid connector such as a cord, cable, chain or strap. The flaccid connector will be rated to withstand the forces required to accelerate the towed vehicle, and may also provide some degree of resilience to reduce these forces and spread them over a greater time interval. While this approach may seem to be the simplest, and certainly requires a minimum of special equipment, the flaccid connector does not maintain spacing between the two vehicles. Consequently, when the towing vehicle decelerates, the towed vehicle must somehow be controlled to also brake or slow down. Most frequently, a second driver occupies the towed vehicle, and applies brakes as required. In the event the second driver briefly loses attention at the same time that the front vehicle slows down, a serious accident may result. In fact, history has demonstrated repeatedly that the second driver is unduly endangered.
A second limitation arises from the design of modern automatic transmissions. Most modern vehicles are equipped with automatic transmissions that cannot be operated under external power. In other words, if the trailing vehicle has a modern automatic transmission, simply shifting the transmission into neutral is not sufficient. Towing the vehicle, even in neutral, may seriously damage the transmission. This is particularly true at highway speeds or if long distances are to be traversed. Consequently, either the transmission must be disconnected from the wheels, or the drive wheels must somehow be lifted from the ground. Disconnecting the transmission is not a task which would be attempted by most persons, and there is no equipment provided in the flaccid connector approach for lifting vehicle drive wheels. Consequently, this technique of using a long flaccid connector between vehicles is normally reserved for situations where one vehicle must only be towed a very short distance, such as from a ditch or hazard back onto the roadway, or for short, low-speed transit such as might occur over a short distance on city streets.
In a second approach to towing, a rigid connector is provided between the vehicles. This may take the form of special linkage that attaches to a ball or other point on the front vehicle, and to the frame, bumper or the like of the trailing vehicle. A ball somewhere within the draft connection is required, since the two vehicles will not always maintain the same planar relationship. For example, when passing through a pot hole or dip in one side of the road, the leading vehicle will tilt from horizontal. However, the second vehicle will not yet be to the dip, and so will still be horizontal. Without the ball or some other articulating connection, undue stresses will be placed upon the vehicles and the draft connection. Balls and mating sockets are preferred for eliminating this undesired stress, owing to their relatively simple construction and the ability for the draft connection to be moved through three dimensions. In other words, through a ball connection the trailing vehicle may move relative to the towing vehicle left and right, up and down, or roll about a longitudinal axis. Consequently, the number of components, complexity and resultant cost are greatly reduced by using a ball connection.
In spite of the many advantages of balls, which are very commonly used in trailers and in some vehicle to vehicle draft connections, the risk of damaging a modern vehicle with an automatic transmission by towing still remains. Several additional approaches have been taken commonly, each which prevent damage to the transmission or drive train of the towed vehicle. In the first approach, the towed vehicle is simply carried upon a larger transport, such as a large flat-bed truck or vehicle transport truck. While this approach works for special purposes such as delivery of new cars or the transport of racing vehicles, it does require that the towing and transport vehicle be very large and have sufficient space for a second vehicle. This limits the use of the towing and transport vehicle to only a few specialized needs, and requires a substantial financial investment in the towing vehicle and storage space when not in use.
In a different approach, the towing vehicle will use a cable or similar flaccid connector to not only engage the towed vehicle, but to lift it off of the ground. This technique is used universally by nearly all commercial tow trucks. Unfortunately, while this technique offers great flexibility in towing very diverse vehicles, a dedicated vehicle with a large boom and winch system is also required. Once again then, a substantial financial investment must be made, and special storage provided for when this special purpose vehicle is not in use.
Another approach incorporates a set of wheels in a small trailer. The towed vehicle drive wheels are driven or placed onto a set of supports between the trailer wheels. The trailer is then connected to the towing vehicle through a ball, allowing multiple axis movement or articulation between towing and towed vehicles. Unfortunately, there are still several drawbacks which arise. First of all, the trailer again requires extra equipment, and also storage space when not in use. A second drawback stems from the extra width required within the small trailer. It must not only be the width of the towed vehicle, but must also have a set of wheels even wider. This extra width is generally undesirable, and, where the towed vehicle is already approaching the legal limits for width, this will lead to an oversize restriction. Further, the set of wheels on the small trailer require maintenance, over and above the maintenance already required by the separate vehicle wheels.
A third drawback is actually characteristic of all ball and hitch connections. When a towed vehicle articulates with respect to the towing vehicle, which may be induced for example by unevenness in the road surface, there is nothing provided to absorb the changes in direction between the towing and towed vehicles. For example, when a towing vehicle travels across a parking lot that slopes downward towards a roadway, both towing vehicle and trailer are in-line and co-axial. However, as the vehicle enters the roadway, the vehicle will change to horizontal. The trailer still points downward. At this moment, the momentum of the trailer would continue the trailer tongue in a direction down into the roadway pavement. Therefore, the towing vehicle ball must not only pull the trailer, but must also lift the trailer tongue. This lifting force results in a shift in the balance of the towing vehicle, effectively reducing the weight of the towing vehicle front wheels. If the transition from parking lot to roadway is sufficiently severe, and the towing vehicle and trailer are close in weight or the towing vehicle has a longer distance between the rear wheels and the hitch, this can actually lead to dangerous lifting of the towing vehicle front wheels or loss of traction. Furthermore, the additional shifting of the towing vehicle reduces the comfort of the ride by transmitting these forces from the hitch into the vehicle cabin. This also places undue stress upon the vehicles and components, requiring a substantial under-rating of the components, so that they can withstand these momentary stresses.
In the prior art, there have been several attempts made at overcoming the limitations of the popular draft connections. U.S. Pat. Nos. 2,452,710 to Allen; U.S. Pat. No. 2,463,140 to Bihn; U.S. Pat. No. 2,966,369 to Paul, Jr.; U.S. Pat. No. 3,223,435 to Yarbrough; U.S. Pat. No. 3,235,286 to Meadowcroft; U.S. Pat. No. 3,239,242 to Adams; U.S. Pat. No. 3,241,862 to Bunting; U.S. Pat. No. 3,250,548 to Boyd; U.S. Pat. No. 3,284,098 to Worley; U.S. Pat. No. 3,311,389 to Barton et al; U.S. Pat. No. 3,680,892 to Olthoff et al; U.S. Pat. No. 3,961,813 to Thomas; U.S. Pat. No. 4,304,419 to Richardson; U.S. Pat. No. 4,351,542 to Lovell et al; and U.S. Pat. No. 4,512,593 to Ehrhardt are each exemplary, and incorporated herein by reference for their teachings. These illustrate a variiety of resilient couplings between two vehicles. Nevertheless, each of these connections only serve as a shock absorber or adjunct to a standard type of hitch, and do not expand or enhance the application of the connection equipment, nor do they fully address the objectives of the present invention.
What is desired then is an articulating connection which allows many diverse loads and vehicles to be towed and transported, without unnecessarily reducing the safety or comfort of the towing vehicle, and not requiring additional passengers or operators other than the single driver of the towing vehicle.